1. Technical Field
The field of the currently claimed embodiments of this invention relates to surgical robots, and more particularly to cooperatively-controlled surgical robotic systems with redundant force sensing.
2. Discussion of Related Art
The SteadyHand micromanipulation robot, disclosed in U.S. Pat. No. 8,911,429, which is hereby incorporated by reference, is a force-controlled surgical device with a primary force/torque sensor located between the last joint of the robot and the surgical instrument adapter. When the surgeon applies a force on the handle of the instrument attached to the adapter, the forces and torques measured by the force/torque sensor are resolved at the handle and the robot complies with the forces and torques by moving the instrument in a corresponding direction. The reliability of the primary force/torque sensor is critical to meeting the stringent safety and efficiency requirements common in surgical applications.
Force/torque sensors are susceptible to many modes of failure due to accidents, misuse, or hazards in the environment. They can provide incorrect measurements from temperature changes, electrical noise, or permanent mechanical deformations. The SteadyHand robot uses a force/torque sensor as the main human interaction input for controlling the motion of the robot. In the case where the measurements are incorrect, it is possible that the robot will react in an unexpected and possibly unsafe manner. This is especially undesirable in high-risk scenarios such as surgery where any undesirable motion of the surgical instrument held by the robot could cause severe injury and even death of the patient. In addition, a robot operating in vicinity of humans should be able to detect the intentions of the operator, detect collisions between itself and objects in its workspace, and have intuitive robot interaction methods. Accordingly, improved systems and methods are needed for ensuring accurate force sensing in cooperatively-controlled surgical robots.